Model airplane control



Mar h 1, 1952 s. J. SPRADLIN 2,538,891

MODEL AIRPLANE CONTROL Filed July 9, 1946 2 SHEETSSHEET .l

I N VEN TOR. Jammy tfi gaaa/m Patented Mar. 11, 1952 UNITED STATES PATENT OFFICE 3 Claims.

My invention relates to model aeroplanes and more particularly to controls for the elevators of such aeroplanes.

The object of my invention is to provide an elevator control mechanism for model aeroplanes adapted to be manipulated by means of a string or the like connected with said mechanism but to be operated at a place distanct from and outside the model aeroplane.

Another object of my invention is to provide a model aeroplane, the rudder whereof is arranged in an offset position relative to the longitudinal vertical center plane of the fuselage to urge the aeroplane to fly toward the outside of the circle of flight.

A further object of the invention is to provide a model aeroplane, the elevator whereof is controlled by a push rod connected to a nut threadedly engaging a spindle rotated by a spool, which in turn can be rotated selectively in clockwise or counterclockwise direction by the ends of a string or the like wound on the spool.

Other objects of the invention not specifically mentioned above may appear in the followin specification describing my invention with reference to the accompanying drawings illustrating a preferred embodiment of my invention.

It is, however, to be understood that my invention is not to be limited or restricted to the exact construction and combination of parts described in the specification and shown in the drawings, but that such changes and modifications can be made, which fall within the scope of the claims appended hereto.

In the drawings,

Figure 1 is a side elevational view of a model aeroplane equipped with an elevator control mechanism according to my invention, the fuselage of the aeroplane being shown as broken open to show the arrangement of the mechanism in the fuselage.

Figure 2 is a detail top plan View in a larger scale of the actuating means of the control mechanism according to my invention.

Fig. 3 is a fragmentary top view of the aeroplane equipped with an elevator control mechanism according tomy invention.

Figure 4 is an end View of a guide arm extending from the fuselage toward the right in relation to the direction of flight and arranged at a level above the right wing of the aeroplane, and

Figure 5 is a sectional view through the guide arm taken on line 5-5 of Figure 3.

Referring now in detail to the drawings the aeroplane model forming the subject matter of my invention has a fuselage l0, which is equipped with two Wings H and a rudder l2. The whole aeroplane is preferably made from a light weight metal, such as aluminum, but can be made from any other suitable material. It can also be equipped with a propelling means, such as a small motor or a rubber hand drive. Since this, however, is not a part of the present invention it is neither shown nor described.

The aeroplane has also a front landing gear l3 and a horizontal stabilizer I4, in which an elevator I5 is hingedly arranged.

Inside the fuselage I0 2. base plate It is pro-' vided and is rigidly supported by the fuselage in any desired and conventional manner. A bearing bracket has a bottom plate I! supported by and firmly attached to the base plate It. The bottom plate I! is rectangular and extends front and aft of the fuselage. On its front and rear end the bottom plate I! has upright extending bearing flanges l8 and I9 respectively. A shaft 20 is rotatably mounted in these flanges, and a spool 2| and spindle 22 are rigidly mounted on the shaft 20.

A clamp nut 23 is mounted on the spindle 22 and engages the same threadedly. It has two upwardly extending flanges 24.

A push rod 25 has a bifurcated front end and the two upwardly extending flanges 24 on the clamp nut 23 are located between the prongs 26 formed by the bifurcation on the push rod 25 and are firmly connected therewith by a pin 21 or the like.

The front edge 28 of the streamlined elevator l5 extends through a hole 29 in the fuselage 10.

A metal strap 38 fits onto the front ed of the elevator and is firmly connected therewith inside the fuselage. This strap 30 has a downwardly extending straight arm 3|, having a hole therein, and the push rod 25 extends through this hole. Spacers 32 are arranged on the push rod 25 adjacent the front and rear surface of the strap arm 3! and washers 33 are welded onto the push rod and abut the spacers 32.

A string 34 is wound onto the spool 2| and consists preferably of a nylon fish line.

A hollow guide arm 35 extends laterally to the right from the fuselage. It communicates with the interior of the fuselage and is firmly connected therewith, so that it is located above the right wing H and the ends of the stringt l extend freely therethrough from the spool 2i.

The guide arm 35 has a streamlined cross section and tapers outwardly from the fuselage. As shown in Figure it is formed by a forward edge member 38 having an arcuate front surface, and a rear edge member 31 having an arcuate rear edge of a much smaller diameter than the diameter of the front edge. These two edge members are connected with each other by a top and bottom strip 38 of balsa wood. The end portion 39 of the guide arm 35, which stops short of the length of the right wing H, is shaped like a rain --drop andhas a plate 48 set into its outer end surface, which is provided with two guide holes 4! allowing the ends of the string 34 to extend therethrough.

While the model aeroplane according to my invention is flying a person operating the aeroplane can cause the same to climb or to dive and, if the driving power should fail, bring it safely in for a landing by manipulating the elevator by selectively pulling cheer the other string ends. This will rotate the spool 2|, the shaft 23 .and :the spindle '22,.so that the clamp nut 23 moves forwardly orrearwardly onsaid spindle and pulls the rod 25 forwardly or pushes .it rearwardly. This movement is transferred to the elevator [5 by the strap arm 31, so that the elevator is pivoted-upwardly or downwardlyas desired.

The rudder 12 is arranged as shown in Fig- .ure 3 so that it is offset from the verticallongi- -tudinal center plane of .the fuselage. When the aeroplane according to my invention .is to be demonstrated, the operator holds .the ends of the :string 34 and starts the propelling .mechanism, so that the aeroplane dies in a circle around theoperator. The offset position of .the rudder urges the aeroplane to fly always in a larger circle, so that the operating string ends :34 will betautened by this trend, thereby facilitating-the operation thereof.

Having described my invention I claim as :new and desire to secure by Letters Patent:

,1. In .a :model airplane including a fuselage :having a horizcntalstabilizer, an elevator {positioned contiguous to said stabilizer and pivotally supported-on the rear edge thereof, andopposed wings projecting from opposite sides of said fuselage and secured thereto, a remotely actuated control operatively connected to said elevator for urging the latter into select positions of its :pivotal movement, said control comprising a GShEftiIJOSitiOneld longitudinally within said fusezlage and rotatably supported therein, a spool circumposed about said shaft at a point intermediate said opposed wings and secured to said shaft, a screw threaded spindle positioned "rearwardly of and in end to end aligned relation with said spool and secured to said shaft, a nut carried on said spindle in threaded engagement therewith and movable'longitudinally therealong in-response to the rotary movement of said shaft, fa control rod positioned interiorly of said fuselage and having one end operatively connected to saidelevator and having the other end operatively connected to said nut for pivotally adjusting the elevator in response to the longitudinal movement ofthe nut, and a control string having an intermediate portion wound about said spool and having its free ends extending exteriorly of said fuselage along one wing thereof for imparting a rotary movement to the assembly of said shaft, spool and spindle.

'2. In a model airplane including a fuselage 'having a horizontal stabilizer, an elevator positioned contiguous to said stabilizer and pivotally supported on the rear edge thereof, and opposed wings projecting from opposite sides of said fuselage and secured thereto, a remotely actuated control operatively connected to said elevator for urging the latter into select positions of its pivtal movement, said control comprising a shaft positioned longitudinally within said fuselage and rotatably supported therein, a spool circumposed about said shaft at a point intermediate said opposed wings and secured to said shaft, a screw threaded spindle gpositioned :rearwardly of and in end to endalin'ged relation with said spool and secured to said shaft, a nut carried on said spindle "in threaded engagement therewith and movable longitudinally therealong in response to the rotary movement of said shaft, a control rod positionedinteriorly of said fuselage and having one end operatively connected to said elevator and having the other end operatively connected to said nut for pivotally adjusting the elevator in response to the longitudinal movement of the nut, a control string having an intermediate portion wound about saidspool and having its free'e'nds extending 'ext'eriorly of *s'aid'fuselage through a hollow guide arm along one wing thereof for imparting a rotary movement to'the assembly of said shaft, spool and spindle, said hollow guide arm being secured at one end to the fuselage and extending along .said one wing and having said one end in communication with the interior of .said fuselage and having the other end terminating contiguous to and .spaced from the wing tip, said guide .arm having its terminating end closed but .provided with a pair of spacedapertures for the extension therethrough of the free ends vof said control string.

3. In .a model airplane including .a fuselage having a horizontal stabilizer, an elevator positioned contiguous to said stabilizerand pivotally supported on the rear edge thereof, and opposed wings projecting from opposite sides of said fuselage and secured thereto, a remotely actuated control operatively connected to said elevator for urging the latter into select positions of its pivotal movement,saidcontrol comprising a shaft positioned longitudinally within said fuselage and rotatably supported'therein, a spool circumposed about said shaft :at a point intermediate said opposed wings and secured'to said shaft, a'screw threaded spindle positioned rearwardly of and in end to end aligned relation with "said spool and secured to said shaft, a nut carried on said spindle in threaded engagement therewith "and movable longitudinally therealong in response to the rotary movement of :said shaft, a controlrod positioned interiorly of said fuselage and "having one end operatively connected'to said elevator :andhaving the other end operatively connected to said .nut 'for'pivotally adjusting the elevator inresponseto'the longitudinal movement of the nut, a control string having an intermediate portion wound about said spool and having its 'free ends extending exteriorly of said fuselage througha hollow guide arm along one wing thereof for imparting a rotary movement to the assembly of said shaft, spool and spindle, said hollow guide arm being secured at one end to the fuselage and extending along said one wing and having said one end in communication with the interior of said fuselage and having the other end terminating contiguous to and spaced from the wing tip, said guide arm having its terminat ing end closed but provided with a pair of spaced apertures for the extension therethrough of the free ends of said control string, said guide arm having a streamline cross section and tapering Number I inwardly from said fuselage toward said Wing tip. 2,321,780 SAMMY J. SPRADLIN. 2,395,530 2,406,874 REFERENCES CITED 5 2,439,054 The following references are of record in the 2,453,571 file of this patent:

UNITED STATES PATENTS Number Number Name Date 20 732 2,292,416 Walker Aug. 11, 1942 Name Date Tondeur June 15, 1943 Barr Feb. 26, 1946 Walker Sept. 3, 1.946 Mosthof Apr. 6, 1948 Barbieri Nov. 9, 1948 FOREIGN PATENTS Country Date Great Britain A. D. 1852 

